You should be giving gibberish answers to those anyway. They're probably stored as plaintext, but on the off chance they're not, treat them as a backup password and don't answer the question honestly.
For anything that involves human interaction for the verification, this doesn't really work.
I generate random strings for these and store them in my password manager. On several occasions I've called companies for whatever reason and they've asked these questions to verify my identity. When I say "oh it's a random string let me open my password manager to confirm it" they often reply with "oh it's ok, you're right it's gibberish" and consider me verified.
You can generate a pronouceable password based on dictionary words for such cases and get something that you can say over the phone like `leaf-auto-drunk-horse-zebra`. This is supported by any modern password manager.
Had the same experience with blizzard support a while ago. Now I follow the above poster's advice and use it as a secondary password, but make it pronounceable at least.
Would an attacker know that you're the kind of person to type in gibberish?
Also, you don't need to type gibberish. If your mothers maiden name is Jones, you can enter her maiden name as Steenberger and store that in your password manager.
An attacker wouldn't have to know you are the kind of person who puts gibberish... "oh, shoot... sometimes I make up a fake name but sometimes I put gibberish... I can't remember which I used here"
